A light emitting diode (LED: Light Emitting Diode) can generate light stably for a long time with relatively low electric power, and is generally used as a light emitting element. A conventional semiconductor device having a light emitting element will be described referring to FIGS. 26 and 27.
As shown in FIG. 26, a conventional semiconductor device 100 has a first lead 101 (a cathode), a light emitting element (a LED die 102) disposed on the first lead 101, and a second lead 104 (an anode) electrically connected to the front surface electrode of the LED die 102 through a bonding wire 103. The portion of the first lead 101 on which the LED die 102 is disposed is formed into a concave shape. This concave portion 105 is plated with silver, for example. Therefore, the concave portion 105 functions as a light reflection surface, by which an attempt is made to enhance the luminance of light emitted from the LED die 102. Furthermore, the components described above are sealed with transparent resin 106.
The lighting on and off of this semiconductor device 100 are controlled by supplying a given voltage from other driver device (not shown) than the semiconductor device 100 to the first lead 101 and the second lead 104.
Furthermore, a conventional photocoupler (Photo coupler) will be described as a semiconductor device having a light emitting element. The photocoupler is a semiconductor device having a light emitting element and a light receiving element, and realizes signal transmission by converting an inputted electric signal into light by the light emitting element and making the light receiving element conductive with the light.
As shown in FIG. 27, a conventional photocoupler 110 has an LED die 111 as a light emitting element and a PD (Photo Diode) die 112 as a light receiving element. The LED die 111 and the PD die 112 are disposed so as to face each other, and electrically connected to leads 114 through bonding wires 113. The LED die 111 and the PD die 112 are sealed with transparent resin 115, and further sealed with mold resin 116 that blocks light. The LED die 111 and the PD die 112 are not electrically connected. In this photocoupler 110, signal transmission is achieved by converting an inputted electric signal into a light signal at the LED die 111 and making the PD die 112 conductive with this light.
Relevant technologies to the invention are described in Japanese Patent Application Publication Nos. 2003-318447 and 2003-347583, for example.
In the conventional semiconductor device 100 (FIG. 26) described above, it is difficult to make the first lead 101 having the concave portion 105, the second lead 104 and so on finer, and all of these need be sealed with the transparent resin 106. Therefore, there is a problem of difficulty in making the whole size smaller. Furthermore, since it is necessary to perform an assembling work after each of the components is completed separately, there is a problem of complex manufacturing processes and an increased cost.
On the other hand, in the photocoupler 110 (FIG. 27) described above, since it is necessary to dispose the LED die 111 and the PD die 112 on the leads 114 so that these face each other, connect the bonding wires 113 to the LED die 111 and the PD die 112, respectively, and so on, it is also difficult to make the whole size smaller and the manufacturing processes are complex.
As described above, a conventional semiconductor device having a light emitting element has a problem of impossibility in making the whole device smaller and thinner and an increased manufacturing cost.